bug#40845: SVG rendering issues

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sat, 22 Aug 2020 20:57:59 +0200 (CEST)
> From: Alan Third <alan@idiocy.org>
> Cc: cpitclaudel@gmail.com, 40845@debbugs.gnu.org, pipcet@gmail.com
> 
> Basically, if you try Clement's original example, when you move the
> mouse over the image the background colour doesn't change to match the
> rest of the line.
> 
> I'm picking up the background colour from the face stored in "it" in
> push_prefix_prop or handle_single_display_spec in xdisp.c. As far as I
> can tell one or both of these are the only places we can define the
> image with the face colours as this is where we actually load the
> image. The problem is that I don't see any way to work out if the
> current image should use the background colour from the mouse face.
> 
> I know that later on we can do (s->hl == DRAW_MOUSE_FACE), but I don't
> think those structures are built yet?

I think you want to modify note_mouse_highlight so that it sets up the
frame's mouse-highlight info for image glyphs, like it currently does
for character glyphs.  It's possible this is all that needs to be
done; if not, we should see how to change show_mouse_face and its
subroutines to display images with mouse-highlight.

Let me know if you need more guidance.